Micro-magnetic sensors are used to detect magnetic fields. Magnetic tunnel junction (MTJ) sensors, for example, detect the presence of magnetic fields using tunnel magnetoresistance (TMR) effects. Such sensors are becoming more commonly used in magnetic read heads, electrical current sensors, magnetometers, electronic compasses, magnetic random access memory (MRAM) and many other settings.
MTJ and other magnetic sensors are generally manufactured on silicon or other substrates using conventional micro-electronic manufacturing techniques. A typical MTJ sensor includes at least two layers of ferromagnetic material separated by a thin insulating tunnel barrier that allows electrons to tunnel between the ferromagnetic layers using quantum mechanical effects. It can be a continual challenge to improve the performance and stability of such sensors.